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Author Topic: Does Solder Have A Shelf Life?  (Read 13912 times)

Posts: 26

« on: April 12, 2002, 09:46:21 PM »

I've got some solder (rosin core) I had in high school (mid '60's). I've used it a few times recently and it seems to work far.

Are there any life limitations to solder? What type should I buy to replace it (for Ham Radio / electronics) and do I need to use a separate flux of some kind?

Can you find all this at a Home Depot type store?

Thanks for any comments / suggestions.

Posts: 3585

« Reply #1 on: April 12, 2002, 10:37:58 PM »

HI: Solder as such has a shelf life that is virtually infinite. The flux may not - but flux is a wetting agent. If your solder does not flow on the work ( the stuff you are soldering) you need to either heat the work more or use new or more flux. For electronic work, that's non-corrosive flux always.

For most electronic work there is very little difference between eutectic 63/37 (percent of tin and lead) and 60/40 solder. The difference in melting point is nil, the 60/40 liquifies a couple of degrees hotter than the eutectic.

In fact, almost all tin lead solders melt at the same temperature but when either the tin or the lead percentage is greater than the eutectic mix there is an increasing temperature range between the softening temperature and the liquifying temperature.

For thin trace PC boards eutectic is slightly better but I worked on PC boards from 1956 to 1987 and never bothered to buy eutectic. But then - 8 hours a day slaving over a hot soldering iron develops at least some skills. Use enough heat - work quickly!

I don't know about your Home Depot, but mine does not stock anything I would care to use for electronic soldering. My local Radio Shack does, as does the local electronic parts store.

Solder brand is pretty much unimportant as long as it is specified to be either eutectic, low melting point, or 60/40 electronic solder. The flux does matter, and must be "rosin core," or specified suitable for electronic work.

My local TV parts store stocks GC chemicals, including both liquid and paste flux. I generally add a drop of GC's liquid flux when solder does not flow.

Lets see - I hope that covers all the bases!

73  Pete Allen  AC5E

Posts: 1435

« Reply #2 on: April 13, 2002, 04:16:38 AM »

Oh NO!

NOS solder!

Posts: 3585

« Reply #3 on: April 13, 2002, 07:36:31 AM »

That's my laugh of the day. I well remember the junk that was marketed to the trade before Ersin came out with their multi-core around 1955. I had all of that stuff I could stand back in the 1940's and early '50's. You do not want NOS solder!

73 Pete AC5E

Posts: 16

« Reply #4 on: April 13, 2002, 02:27:57 PM »

Yes, solder does have a shelf life.
Solder lasts until there's a fire.

Posts: 8

« Reply #5 on: April 15, 2002, 03:07:53 PM »

     I have to disagree with the statement that 60/40 works just as well as 63/37.  Perhaps in a well controlled, environment with correct temperature, humidity and air circulation, but not with "real world" conditions.  60/40 has a "freezing point" temperature at which the solder suddenly solidifies.  You can see this by melting a bunch of it into a "pool" with your iron and watching the sudden wave of crystallization sweep across the "blob" (played around with that in my younger days).

  When soldering at a good soldering station where the parts are held steadily together and you don't have any air blowing onto the joint, this is no problem.  I you are holding the parts together with "shaky" hands or if outdoors and a wind is blowing on the joint, you run a very good risk of having a "cold solder joint".  It's easily recognized by having a dull gray look rather than a bright, shiny finish.  A cold solder joint is very bad both mechanically and electrically.

   63/37 solder does not have a "freezing point", it transitions smoothly from a liquid to a solid and you do not get cold solder joints (at least I haven't been able to make one, and I've even deliberately tried, just to see if the claims are true).  This makes 63/37 work well when soldering in less than ideal conditions, like in your drafty garage, outdoors while up on a ladder, or crouched under the dashboard of your car.  The small cost differential per roll (usually less than $1 for a 1 lb roll) makes it worth it if you have a choice.  If you also have a choice, go for the "no clean" type of flux.  In critical situations, you should always clean your solder joint of flux, but if you don't, the "no clean" flux is non-corrosive and looks just about as good as if you cleaned that "brown stuff" off of a solder job where rosin flux was used.

   As for expiration dates, yes the solder does have an expiration date, but that is for situations such as NASA or DoD work where tractability is critical and vendors are being allowed to use more off the shelf parts and consumables nowadays.  Putting an expiration date on a roll of solder is like putting a "best if used by" date on a quart of motor oil.

That's my observation.  If I've goofed somewhere, please let me know.

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